Set partial pixel to be transparent in video

[Sean]

Hi, Peter,

Thanks for pointing out the "byte-ordering" of RGBA in Gstreamer. However,
if we don't care the performance and only care the correctness. I think the
following implement should work in myelement (i. e. writing the 4th byte of
each pixel):


    for (int i  = 0; i < 240; i++) {
      for (int j = 0; j < 640; j++)
      info.data[(i*640+j)*4-1] = 0x0;
    }

However, the result is the same (i.e. the pixel at (row,col)=(0,4), (0,8)
(0,12)...... become a GREEN pixel). Is it related to the "stride" value? If
yes, how would I get stride information? I checked "GstMapInfo" which
doesn't have stride information? 

Thanks.



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